# Definition for a binary tree node.
class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right
from typing import Optional

# 题目链接:https://leetcode.cn/problems/same-tree/description/?envType=study-plan-v2&envId=top-interview-150
class Solution:
    def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        if p is None and q is None:
            return True
        if p is None and q is not None:
            return False
        if p is not None and q is  None:
            return False
        if p.val != q.val:
            return False
        return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)
